Visa print out, rental agreement copy and some app where u can access your bank balance and show it to them, if you want to practice extra caution.

If no current income better to wait 3 months and take soft power route

For PR you need to be a tax resident for 3 years, im not too sure if the type of visa matters as much as your contribution to nations coffers in terms of tax, usually taxable income that qualifies does have a lower bound, i dont remember the exact amount, taxable income of 85k a month I think.

In short whether you spring for dtv or ltr make sure you meet the tax contribution requirements either as an investor or business owner.

Usually 2k thb fine but if immigration officer doesnt notice or care and u get stamped in then no issues.